Projected and secured virtual keyboard

ABSTRACT

The invention relates to a method for inputting a text in a distributed system that comprises a secured device, or server, communicating with at least one electronic device, or terminal. The method makes it possible to prepare an image by associating certain values to areas defining said image. The image is projected to the user who can touch the areas of the images that he wants to select as he would do with the keys of keyboard. The finger movements are analysed and the position of the virtual keys selected by the user is transmitted to the server that establishes a correlation between these positions and the previously associated values.

BACKGROUND OF THE INVENTION

The invention relates to a projected and secured virtual keyboard.

The invention more particularly relates to a method for inputting a textbased on the positioning space of the fingers while referring to aprojected image.

The European patent EP980039 describes a method for inputting charactersthrough a virtual keyboard. A virtual keyboard is a means for inputtingtexts in the absence of a peripheral unit including one key percharacter and which is more particularly intended for equipment such asinteractive television, cellular phones or personal terminals PDAs.Virtual keyboards can also be applied in the field of secured exchanges.

Patent PCT W09914657 is known in the state of the art and discloses avirtual keyboard used on a computer screen to emulate a conventionalkeyboard. The coordinates of the keys of the virtual keyboard are storedin a memory as a table, by the computer. The key coordinates are sortedin the table as a function of their occurring frequency. A pointingdevice makes it possible to select the keys on the virtual keyboard. Theinput points generated by the pointing device are compared one by one tothe coordinates of the keys kept in the coordinates table. To decidewhether the input point matches a considered key, defined criteria areapplied to a terminal function. If they match, the key is affected tothe input point and the search stops. The search for the matching keygoes on until a match is detected or until the end of the table.

The American patent U.S. Pat. No. 5,008,847 discloses another type ofvirtual keyboard including a means of selection by a cursor moved on agraphic representation of a keyboard.

These prior art solutions have the drawback of having a fixed geometryand of being easily spied on within the scope of the inputting of secretinformation. In addition, the prior art solutions are particularlyvulnerable in case of presence of an hostile module on the electronicdevice in charge of presenting the virtual keyboard.

BRIEF SUMMARY OF THE INVENTION

The object of the present invention is to remedy this drawback byproviding a secured method for inputting a text using a virtualkeyboard.

Firstly, the invention is a method for inputting a text in a distributedsystem that comprises at least a secured device called a server,communicating with at least one electronic device called the terminal,and the method includes at least:

-   -   a step of pre-calculation wherein at least one look-up table is        established an image, at least an area of the image, and at        least a value,    -   a step of transmission of the image from the server to the        terminal,    -   a step of projection by the terminal of the image towards the        user,    -   a step of identification of the positions in space of the user's        fingers in relation with the projection of the image,    -   a step of restitution of the positions in space to the server,    -   a step of interpretation by the server of the positions received        in relation with the look-up table so as to obtain values of        so-called candidate values.

The projection can be executed against a surface which is used as ascreen.

In one embodiment, the image shows several geometrically distinct areas.Such areas can form a set of keys.

In one embodiment, the look-up table makes it possible to apply thepositions to a second image.

In one embodiment, the look-up table makes it possible to apply shiftsto the positions so as to obtain corrected positions.

In one embodiment, the method also includes a previous step during whichthe image can either be selected among a list of images saved in amemory which can be accessed by the server, or generated.

The invention is also a terminal for inputting a text in relation withat least one secured device called a server, this terminal includesmeans for

-   -   receiving from the server an image    -   projecting this image onto a support to a user    -   identifying the positions in space of the user's fingers in        relation with the projection of the image    -   restituting the positions in space to the server.

In one embodiment, the means of identification of the positions in spaceof the user's fingers can be video capture means, pressure sensorspositioned in said projection medium or radar emitters and receivers.

The advantage of the invention is that the image sent by the server isnot interpreted by the terminal. As a matter of fact, since the image ismonolithic and not dissociated into areas, it makes the terminal unableto interpret the fingers positions that it noted.

Now, the method is particularly adapted to a case where the server doesnot trust the terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and advantages of the invention will clearlyappear upon reading the following description thereof, which is given asan indication and not as a limitation, while referring to the appendeddrawings wherein:

FIG. 1 shows an exemplary implementation of the invention;

FIG. 2 shows an exemplary implementation of the invention with anintermediate device intended for establishing the communication betweenthe terminal and the server;

FIG. 3 shows an exemplary image which can be used by the inventionwherein the graphic areas showing the keys are positioned in a circle;

FIG. 4 shows an exemplary image which can be used by the inventionwherein the graphic areas showing the keys are mixed;

FIG. 5 shows an exemplary image which can be used by the inventionwherein the graphic areas showing the keys are shown as a geographicmap;

FIG. 6 is an illustration of an implementation of the invention wherethe projection of the image makes a positive angle with the supportingangle;

FIG. 7 is an illustration of an implementation of the invention wherethe projection of the image is on a surface sensitive to pressure.

DETAILED DESCRIPTION OF THE INVENTION

The invention may be schematically and not limitatively a method forinputting a text in a distributed system that comprises at least asecured device called a server, communicating with at least oneelectronic device called the terminal.

This method can, among other things, make it possible to prepare animage by associating values with some areas which it is composed of.

This image is projected to the user which will touch the areas of theimage he wishes to select, as he would do for the keys of a keyboard.

The motions of the fingers are analysed and the positions of the virtualkeys that he selected are transmitted to the server which will make thecorrelation between these positions and the previously associatedvalues.

Thus, FIG. 1 illustrates an implementation of the invention wherein auser tries to access a remote service, hosted by a server 2, via anetwork 4. In order to authentify the user, the server 2 transmits 3 animage to a terminal 1 which is directly in contact with the user. Thisterminal is provided with means making it possible to display 5 thereceived image to the user's view. In the example illustrated in FIG. 1,the display of the image is executed by a projection onto a medium. In aprevious step, the server 2 “builds” the image by identifying thereonparticular areas which information is associated with. An example is theimage of a numeric keypad and to each one of the areas matching each oneof the keys is associated the value of a key. In another example, ageographic map of a country can be divided into areas and a value can beaffected to each one of these areas. According to the embodiments, thecorrelation information between the image and the areas and theassociated values can be stored in a memory of the server or in anyother memory accessible by the server.

In one particularly advantageous implementation of the invention, thiscorrelation information can be saved in a secured electronic device.This secured electronic device can be for example a secured mobiledevice giving independence to the functionality of the server and of theserver hardware. Any communicating electronic device may potentiallybecome a server if it is placed in contact with the secured mobiledevice which contains the correlation information.

The terminal 1 is provided with means making it possible to analyse themotions about the projection 5. This analysis includes several steps andseveral devices. As a matter of fact, such an analysis includes acapture of motions close to the displayed image 5 and the analysisthereof in order to extract positions from said inputs. Such inputtingpositions will represent the selection by the user of geographic areasof the image 5. A particularly explicit illustration of this analysis isgiven by the example where the image 5 shows a computer keypad. The userputs his fingers close to the surface of the image 5 and places hisfingers on the areas of the image which correspond to the keys of thedigital code he wants to input. Then, the analysis according to theinvention consists in capturing the motions of the user's fingers closeto the image 5 of the digital keyboard 5, and analyses these so as toprovide positions corresponding to the areas touched by the user.

In the example illustrated in FIG. 1, such an analysis can be executedby using video capture means 6. Any other means for identifying themovement of a physical object in a defined space can be used foranalysing the motions and these are solutions which can be used. In aparticular implementation, two cameras are associated together in orderto obtain an optimum accuracy in the motion analysis. In one embodiment,the video capture means can have, with the display medium 5, a positiveangle as illustrated by FIG. 6.

Such analysis is sent back 7 to terminal 2 which will in turn processsuch data in relation with the information of correlation between theimage 5, the areas composing it and the values associated thereto.

The result of this authentication will decide on the further actiongiven to the user's request.

FIG. 2 illustrates an implementation of the invention wherein theterminal 11 is in relation with the server 12 thanks to a communicatingelectronic device 16, which is itself able to communicate with theserver 12 through a network 14, for example radiotelephony. Thisembodiment is particularly adapted to the case where the communicatingelectronic device and the server offer the user a service requiring ahigh authentication, for example a banking service. Considering thelarge diversity of the communicating electronic devices, it is verydifficult for the server to build the security of the service on adevice which is it does not control and for which is not able toguarantee safety. By associating the terminal with the electronicdevice, the server authenticates the user through the communicationchannel represented by the electronic device without being afraid ofpossible security flaws therein. As a matter of fact, the communicatingdevice as well as the terminal, sees an image sent in one direction andpositions sent in another direction, but without having informationmaking it possible to correlate both and to extract operational valuestherefrom. In a particularly advantageous mode of the embodiment, theterminal has authentication means which are its own and can beauthentified with the server so that the exchanges 13 and 15 can becarried out through a secured communication channel, for example using asession key, which still reinforces the system safety.

In FIGS. 3, 4 and 5 various exemplary images can be seen which can beused according to the invention. FIG. 3 illustrates the case where theareas composing the images are mixed together, so that the geography ofthe virtual keyboard shown by the images changes. Similarly, FIG. 4illustrates the case where geography of the “virtual keyboard” remainsunchanged, but the values of the areas are rearranged. Both techniquescan advantageously be combined to vary both the organisation of areasand their sequences. In a particularly interesting embodiment of theinvention, during each session the sent image is either selected among apre-defined list of images, or generated. This precaution makes itpossible to get protection against a possible recording of exchangesbetween the terminal and the server during several sessions, and to makea correlation between the information supplied by each recording.

FIG. 5 shows an exemplary image through which information is inputthrough a symbolic convention. For example, the image can represent aseries of colours and the convention between the user and the server isthat the user must select the blue, green and red colours.

FIG. 6 illustrates an implementation of the invention wherein the meansfor analysing the motions at the periphery of the projection of theimage according to the invention makes a positive angle with thesupporting angle. The terminal according to the invention is shown inFIG. 6 by the element 51. In this example, the terminal 51 projects animage 55 onto a plane 56. This plane can for example be a plane surfaceon which the terminal will be positioned. The terminal further has means52 for analysing motions. As illustrated by the symbolic axis 53, thismeans is oriented so as to analyse motions at the direct periphery ofthe projection 55 of the image. FIG. 6 illustrates the particularlyadvantageous case where the analysis means 52 has an angle 54 which ispositive to the surface of projection 56. This particular implementationsignificantly increases the performances of the motion analysis. Anangle 54 close to 90 degrees will give large facilities for an analysis.

In another embodiment, FIG. 7 illustrates the case where the device 61projects an image 65 according to the invention on a surface 62sensitive to pressure. This surface 62 will then be able to identify theplaces where the user puts his fingers on the surface thereof and torestitute this analysis to the terminal 61.

An additional advantage of the invention is that, contrary to thestandard inputting means, the use of an input terminal according to theinvention leaves no trace on the keyboard after it has been used, sincethe disappearance of the image eliminates any reference at the sametime. Similarly, it is not possible to study a possible wearing of thekeys in order to deduce possible information therefrom.

The invention claimed is:
 1. A method for inputting a text in adistributed system that comprises at least a secured device or servercommunicating with at least one electronic device or terminal, whereinthe method includes: a step of pre-calculation wherein at least alook-up table is created between an image, at least an area in saidimage, and at least a value, a step of transmission of said image fromsaid server to said terminal, a step of projection by said terminal ofsaid image to a user, a step of identification of the positions in spaceof the user's fingers in relation with said projection of said image, astep of restitution of said positions in space to said server, and astep of interpretation by the server of the received positions inrelation with said at least one look-up table in order to obtaincandidate values.
 2. A method according to claim 1, wherein saidprojection is executed against a surface which is used as a screen.
 3. Amethod according to claim 1, wherein said image shows severalgeometrically distinct areas.
 4. A method according to claim 3, whereinsaid image defines a set of keys.
 5. A method according to claim 1,wherein said look-up table makes it possible to apply said positions toa second image.
 6. A method according to claim 1, wherein said look-uptable makes it possible to apply shifts to said positions in order toobtain corrected positions.
 7. A method according to claim 1, whereinsaid image is selected from among a list of images saved in a memorywhich can be accessed by said server.
 8. A method according to claim 1,wherein said image is generated in a step preceding said pre-calculationstep.
 9. A terminal for inputting text in relation with at least onesecured device or server, wherein the terminal includes means for:receiving, from said server, an image projecting said image onto amedium for receiving by a user identifying the positions in space of theuser's fingers in relation with such projection of said imagerestituting said positions in space to said server.
 10. A terminal forinputting text according to claim 9, wherein said means for identifyingthe positions in space of the user's fingers are video capture means.11. A terminal for inputting text according to claim 9, wherein saidmeans for identifying the positions in space of the user's fingers arepressure sensors positioned in said projection medium.
 12. A terminalfor inputting text according to claim 9, wherein said means foridentifying the positions in space of the user's fingers are radaremitters and receivers.